Dielectric and optical measurements from 30 to 1000 GHz

A review is presented of current measurement methods for the determination of dielectric and optical properties of materials at frequencies between 30 and 1000 GHz. The methods considered will fall into four main categories based on guided, resonant, free-space and stirred-mode geometries. The main applications of the measurements considered are in the study of materials that are relevant to telecommunication and radar developments. The significance of dielectric measurements for physicochemical and biomedical studies is also briefly discussed. Among the methods covered are those based on waveguide bridges, closed cavities and open resonators, Fourier transform spectrometry and laser methods. The relatively new field of stirred mode (or untuned) cavity dielectric measurements is introduced and discussed. The application of these methods is illustrated by reference to measurements on low-loss solids, highly reflecting surfaces, liquids, composite materials and, briefly, on biological materials and gases.